president obama is cancelling his thursday morning meetings at the white house to travel here to boston to honor the victims of monday's marathon bombings. we have been told he will speak at an interfaith service here, speaking late yesterday morning at the white house calling this a cowardly terrorist act. >>> if you would like to help those affected by monday's devastating terrorist attack there is a way, cnn.com/impactyourworld. >> many people needing blood in boston specifically. stay with cnn for live continuing coverage of the boston marathon attack, including chilling new photos here of the explosive device that inflicted all this pain and suffering. who did it? why did they do it? many, many questions this early wednesday morning. >>> plus there is another very big developing story overnight. a letter addressed to a u.s. senator testing positive for the deadly poison ricin. where that investigation stands right now this morning. you're watching a special edition of "early start." lactose-free lactaid® it's 100% real milk that's easy to digest so you can fully enjoy the dairy yo